Resistance device for fitness and bodybuilding equipment

ABSTRACT

A resistance device for use with an exercise machine includes an arbor member structured to be rotatably coupled with respect to the exercise machine. The arbor member having a first end and an opposite second end. The resistance device further having a first hub coupled to the arbor member, the hub having a contact portion of variable radius; a cord member having a first end and an opposite second end, the first end being coupled to the arbor member at or about the first hub, the cord member wound about the first hub at the contact portion; an elastic element having a first end and an opposite second end, the first end being coupled to the second end of the cord member and the second end being structured to be coupled to a point fixed relative to the exercise machine; a second hub coupled to the arbor member, the second hub being structured to be coupled to a user actuatable member; and an adjustment mechanism coupled to the first hub, the adjustment mechanism being adapted selectively to vary the radius of the contact portion of the first hub.

BACKGROUND

1. Field of the Invention

The invention relates generally to resistance devices and, more particularly, to resistance devices for use with exercise machines.

2. Background Information

Known fitness and bodybuilding devices, despite their size and diversity, are generally made up of four basic parts: (1) a support structure, (2) a resistance unit, (3) one or more terminals for performing different exercises and (4) a transmission providing a physical coupling between the one or more terminals and the resistance unit. Resistance units typically utilize weights, elastic elements (springs or rubber bands) and/or frictional elements (mainly rubbing discs) in order to create resistance, which the person operating the device while exercising must exert a force to surmount.

For the major part of such devices, different metal slabs or discs with fixed (definite) mass are used as force elements. Commonly, the mass of such weights is commensurable or heavier than the whole construction. Whenever a change in the resistive load is needed, the person exercising typically moves a fixing peg relative to the weights to load or unload the device with a certain number of metal weights. The load is thus changed in a step-like manner, where the difference between two neighboring steps or levels depends on the mass of the separate weights being added or removed. As the weights rely on gravity, the weights must move only in a vertical, or near vertical direction, which requires a considerable volume of the device construction.

Accordingly, there is room for improvement of known fitness and bodybuilding devices, particularly in resistance systems employed therein.

SUMMARY OF THE INVENTION

Such deficiencies in the prior art are addressed by embodiments of the invention which are directed to a resistance device for use with an exercise machine and an exercise machine.

As one aspect of the invention, a resistance device for use with an exercise machine is provided. The resistance device comprises: an arbor member structured to be rotatably coupled with respect to the exercise machine, the arbor member having a first end and an opposite second end; a first hub coupled to the arbor member, the first hub having a contact portion of variable radius; a cord member having a first end and an opposite second end, the first end being coupled to the arbor member at or about the first hub, the cord member wound about the first hub at the contact portion; an elastic element having a first end and an opposite second end, the first end being coupled to the second end of the cord member and the second end being structured to be coupled to a point fixed relative to the exercise machine; a second hub coupled to the arbor member, the second hub being structured to be coupled to a user actuatable member; and an adjustment mechanism coupled to the first hub, the adjustment mechanism being adapted selectively to vary the radius of the contact portion of the first hub.

The arbor member may comprise a number of guide members coupled thereto. The first hub may comprise a conical shaped member of varying radius moveable with respect to the number of guide members by the adjustment mechanism. The adjustment mechanism may comprise a crank member threadedly coupled to the first hub. The elastic element may comprises a spring member. The elastic element may comprise a beam member. The elastic element may comprise a torsionally deflected member.

As another aspect of the invention, an exercise machine is provided. The exercise machine comprises: a frame; a user actuatable member moveable relative to the frame; and a resistance device comprising: an arbor member structured to be rotatably coupled to the exercise machine, the arbor member having a first end and an opposite second end; a first hub coupled to the arbor member, the hub having a contact portion of variable radius; a cord member having a first end and an opposite second end, the first end being coupled to the arbor member at or about the first hub, the cord member wound about the first hub at the contact portion; an elastic element having a first end and an opposite second end, the first end being coupled to the second end of the cord member and the second end being be coupled to a point fixed relative to the frame; a second hub coupled to the arbor member, the second hub being coupled to a user actuatable member via a flexible member; and an adjustment mechanism coupled to the first hub, the adjustment mechanism being adapted to selectively vary the radius of the contact portion of the first hub.

The arbor member may comprises a number of guide members coupled thereto; and the first hub may comprises a conical shaped member of varying radius moveable with respect to the number of guide members by the adjustment mechanism. The adjustment mechanism may comprise a crank member threadedly coupled to the first hub. The elastic element may comprise one of a spring member, beam member, or torsionally loaded member.

BRIEF DESCRIPTION OF THE DRAWINGS

A full understanding of the invention can be gained from the following description of the preferred embodiments when read in conjunction with the accompanying drawings in which:

FIG. 1 is a schematic view of an exercise machine employing a resistance device according to a non-limiting embodiment of the present invention in which an arbor member of the resistance device is in a first position;

FIG. 2 is a schematic view of an exercise machine employing a resistance device as shown in FIG. 1 with the arbor member of the resistance device disposed in a second position;

FIG. 3 a is partial cut away side view of an arbor member of the resistance device of FIG. 1;

FIG. 3 b is a sectional view of the arbor member of FIG. 3 a taken along line B-B of FIG. 3 a;

FIG. 3 c is an end view of the arbor member of FIG. 3 a taken along C-C of FIG. 3 a.

FIG. 4 is a schematic view of a portion of an exercise machine employing a torsionally loaded elastic member according to a non-limiting embodiment of the present invention;

FIG. 5 is a schematic view of a portion of an exercise machine employing a bending elastic member according to a non-limiting embodiment of the present invention;

FIG. 6 is a schematic view of an exercise machine employing a resistance device according to another non-limiting embodiment of the present invention; and

FIG. 7 is a schematic view of an exercise machine employing a resistance device according to yet another non-limiting embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Directional phrases used herein, such as, for example, left, right, front, back, top, bottom and derivatives thereof, relate to the orientation of the elements shown in the drawings and are not limiting upon the claims unless expressly recited therein. Identical parts are provided with the same reference number in all drawings.

As employed herein, the term “number” shall be used to refer to any non-zero quantity (i.e. one or any quantity greater than one).

As employed herein, the statement that two or more parts are “coupled” together shall mean that the parts are joined together either directly or joined through one or more intermediate parts.

The present invention provides a generally small, compact and simple-constructed device, which eliminates the defects and drawbacks of previously known resistance devices. Moreover, it is foreseeable that the present invention will lead to a new construction with multifunctional usage, where electronic technologies for programming whole cycles of exercises can be applied and calculation of the energy (calories) consumed by the exerciser can be made.

A device constructed according to the present invention operates by converting the variable force necessary for the deformation of an elastic element (subject to Hooke's Law) into an unspecified force with constant magnitude. This is accomplished by employing an elastic element, which is fixed on one end and the other end is fastened to a flexible thread (e.g., a rope, a belt, a chain, etc.). The loose end of the elastic thread is joined together with a cone-shaped hub or a hub whose diameter can change its size without ratio. On the same shaft or on another, coupled together with an appropriate transmission, a hub is mounted with a channel of Archimedean spiral or coneshaped hub with a conical thread (carving), shaped like a channel for the elastic fiber. Another elastic fiber lies in this channel, fixed in one end to the hub, while on its loose end is applied a certain external force by a user of the device. This force, which is constant in magnitude, puts the system in motion.

Having thus described a general overview of the invention, a detailed description of a non-limiting example embodiment will now be provided in conjunction with FIGS. 1, 2 and 3 a-3 c. Referring to FIG. 1, a resistance device 8 for use in, or in conjunction with, an exercise machine 10 (shown schematically in hidden line) is shown. Resistance device 8 includes a generally hollow arbor member 11 that is rotatably coupled to the exercise machine 10, preferably via a number of bearings 12 (FIG. 3 a), such that arbor member 11 rotates about an axis A. It is to be appreciated that “coupled to the exercise machine” as used herein shall mean that the particular item is coupled to at least a portion of the exercise machine such as, for example, without limitation, a frame or other member.

A first hub 14 of generally conical shape is slidably disposed on arbor member 11 such that first hub 14 may move relative to arbor member 11 generally along axis A. First hub 14, includes a number of axial openings or slots 16 (FIGS. 3 a and 3 b) through which a number of guide members 18 extend. Each of the number of guide members 18 is coupled in a fixed manner to arbor member 11. Such arrangement allows for first hub 14 to move relative to both arbor member 11 as well as guide members 18, as is shown in the example of FIGS. 1 and 2 discussed further below. As shown in FIG. 3 b, preferably each of the number of guide members 18 are disposed generally evenly spaced about arbor member 11.

An adjustment mechanism 20, disposed generally at a first end 21 of arbor member 11, is adjustably coupled to the first hub 14 to control/adjust the relative position of the first hub 14 on arbor member 11. In the example embodiment depicted generally in the Figs. and in particular detail in the partial cut away view of FIG. 3 a, adjustment mechanism 20 comprises a knob or crank 22 having a threaded adjusting screw 24 which is coupled thereto and extends therefrom generally along axis A. Adjusting screw 24 interacts with a threaded nut 26 that is coupled to first hub 14 via a special key 28. The key 28 is disposed in a channel 29 formed in arbor member 11. By turning the crank 22 in one direction or the other, as indicated by arrow R (FIG. 3 a), first hub 14 moves axially along axis A either into greater overlap with guide members 18, as shown in FIG. 1, or into lesser overlap with guide members 18, as shown in FIG. 2. It is to be appreciated that crank 22 may be manually adjusted by a user or operated via other mechanism. It is also to be appreciated that other arrangements could be employed in lieu of adjustment mechanism 20 to vary the position of first hub 14 on arbor member 11 without varying from the scope of the present invention. As an example, a linear actuator could be coupled to first hub 14 in a manner that selectively adjusts the axial position of first hub 14 on arbor member 11.

Arbor member 11 further includes a second hub 30, preferably including channels of Archimedean spiral, fixedly coupled at or about a second end 31 of arbor member 11. It is to be appreciated that the use of a hub including channels of Archimedean spiral works to transform the constantly growing force exerted by an elastic element, as discussed in detail below, into a constant force (i.e., as the force due to the elastic element grows, so does the radius of the Archimedean spiral).

FIGS. 1 and 2 show examples of the general working scheme of the resistance device 8 within an exercise machine 10. In use, a rope 32 or other suitable member having a user interface, such as a handle 33 coupled at a first end thereof, is fixed at a second end to the second hub 30 at or about the furthest point from axis A and is coiled up to the channel of the spiral to its smallest diameter. A second rope or cord 34, or other suitable member, is coupled at a first end (not numbered) to arbor member 11 at or about the guide members 18. A second end 36 of cord 34 is coupled to an elastic member (subject to Hooke's Law) such as cylindrical spring 38 at a first end 40. A second end 42 of spring 38 is coupled to a point 44 fixed with respect to the arbor member 11 (e.g., without limitation, a frame member of exercise machine 10). Although embodied as a spring in the example embodiment depicted in FIGS. 1 and 2, it is to be appreciated that other suitable elastic members may be employed without varying from the scope of the present invention. Suitable elastic members are generally those members which elastically deform in a predictable manner proportional to the force applied to them. FIGS. 4 and 5 show non-limiting examples of other elastic members that may be used in place of the cylindrical spring 38 of FIGS. 1 and 2.

For example, the arrangement of FIG. 4 utilizes a rod 38′ as an elastic member disposed to be distorted in a torsional fashion. Preferably, rod 38′ is formed from metal or other suitable rigid material and may be solid or of generally hollow construction. Rod 38′ includes a first end 40′ having a pulley 41 of constant diameter fixedly coupled thereto. Pulley 41 preferably bears on, and is freely rotatable with respect to, a fixed portion 44 of the frame, or other suitable portion of the exercise machine and includes a groove 43 disposed thereabout. Similar to the arrangement of FIG. 1, the second end 36 (not labeled in FIG. 4) of cord 34 is coupled to the pulley 41 and at least a portion of cord 34 is wound thereabout in groove 43. Rod 38′ further includes a second end 42′ fixedly coupled to another fixed portion 44′ of the frame, or other suitable portion of the exercise machine. In use, displacement of cord 34 as a result of an applied force f causes rod 38′ to elastically distort in a torsional fashion, similar to the linear distortion of cylindrical spring 38.

FIG. 5 shows another example arrangement that utilizes a beam or bar 38″ as an elastic member disposed to be distorted in a bending fashion (as shown in phantom line). Preferably, bar 38″ is formed from metal or other suitable material and includes a first end 40″ and a second end 42″. Similar to the arrangement of FIGS. 1 and 4, the first end 40″ of bar 38″ is coupled to the second end 36 of cord 34. The second end 42″ of metal bar 38″ is fixedly coupled to a fixed portion 44′ of the frame, or other suitable portion of the exercise machine. In use, displacement of cord 34 as a result of an applied force f causes bar 38″ to elastically deflect in a predictable bending fashion (shown in phantom line), similar to the predictable linear distortion of cylindrical spring 38.

Referring again to the arrangement shown in FIGS. 1 and 2, the coupling of cord 34 to arbor member 11 at or about the guide members provides for cord 34 to be wound around first hub 14 upon rotation of arbor member 14, as will be described in greater detail below. Through the use of adjustment mechanism 20, the portion of the conical surface of first hub 14, and thus the effective radius R of the portion of the surface that is engaged by cord 34 can be selectively varied. For example, when first hub 14 is positioned as shown in FIG. 1, the effective radius R₁ is greater than the effective radius R₂ when first hub 14 is positioned in another position as shown for example in FIG. 2. Accordingly, the force F required to move handle 33 is less when first hub 14 is positioned as shown in FIG. 2 than when positioned as shown in FIG. 1.

Having thus described the basic layout of an example exercise machine 10 according to a non-limiting embodiment of the invention, a brief description of how the force F required to pull handle 33 is determined and adjusted will now be provided. In operation, there are two moments of force that act upon arbor member 11, one resulting from the force F applied by a user of the exercise machine 10 to second hub 30, and the other resulting from the resistive force of the elastic element, such as spring 38.

Referring to FIG. 1, in use, arbor member 11 is rotated by a user providing the required force F to handle 33, and thus rope 32 which, as previously described, is coiled around second hub 30. The angle φ of such rotation can be measured in radians. If the force F is applied a known distance R_(o) from axis A, the moment M_(F) of the force F is described by the equation:

M _(F) =FR _(o)

If we mark the arm of the force F for every φ with the equation:

φ=R _(o)φ/2π

the moment M_(F) of force F can then be expressed by the equation:

M _(F) =FR _(o)φ/2π

Continuing to refer to the example of FIG. 1, the force moment M_(E) on arbor member 11 relative to rotational axis A due to spring 38 is governed by the equation:

M _(E) =F _(E) R ₁

where F_(E) is the force exerted by the elastic element, spring 38 and R₁ is the distance such force F_(E) is spaced from the rotational axis A (i.e., the effective radius of the first hub 14 as shown in FIG. 1). The force F_(E) of the displaced spring is governed by the equation:

F _(E) =kx

where k is the spring constant of spring 38 (typically expressed in kg force/mm) and x is the distance spring 38 is displaced from a given position. The distance x that spring 38 is displaced by rotation of arbor member 11 an angle φ is described by the equation:

x=2πR ₁φ/2π=R ₁φ

where R₁ is the radius of the portion of first hub 14 around which cord 34 is being wrapped due to turning of arbor member 11 of FIG. 1, and φ, as described above, is the angle of rotation of arbor member 11 as measured in radians (i.e., 2π radians=360 degrees).

Hence, the moment M_(E) on arbor member due to spring 38 can be described by the equation:

M _(E) =k×R ₁ =R ₁ ² φk

Thus, the force F can be calculated by equating the moments acting on the arbor member 11, wherein:

M _(F) =M _(E)

Substituting the value for above we then get the equation:

FR _(o)φ/2π=R ₁ ² φk

From which F can readily be determined as:

F=2πR ₁ ² k/R _(o)

Thus the force F required to rotate arbor member 11 is determined by the spring constant k of spring 38, which, by definition, is a constant value dependent on the elastic member utilized, the radial distance R_(o) from axis A which force F is applied, which would be known from the sizing of second hub 30, and the effective radius R₁ of the first hub 14, which is adjustable via adjustment mechanism 20 as previously described herein. From such equation it is readily apparent that the force F required to rotate arbor member 11 of FIG. 2 is less than that required in FIG. 1 as the effective diameter R₂ of first hub 14 in FIG. 2 is less than the effective diameter R₁ of first hub 14 in FIG. 1.

FIGS. 6 and 7 show further example embodiments of exercise machines 10′ and 10″ according to further non-limiting embodiments of the present invention. More particularly, FIG. 6 depicts an exercise machine 10′ that utilizes a resistance device 8′ similar to resistance device 8 previously discussed in regard to FIGS. 1 and 2 except for the addition of a gearset 50 which may be used to selectively adjust the entirety of the resistance range provided by the elastic element 38 and/or to adjust the sizing of the pulley 30′ utilized. FIG. 7 depicts an exercise machine 10″ that utilizes a resistance device 8″ similar to resistance device 8 except a torsionally distorted elastic element 38′, such as described in FIG. 4, is utilized. Another difference in such embodiment shown in FIG. 7 is that second hub 30 (including channels of Archimedean spiral) is coupled to first end 40′ of elastic element 38′ and a pulley 41 (of constant diameter) is coupled at or about the second end 31 of arbor member 11.

From the examples provided herein, it can be readily appreciated that the resistance devices 8, 8′, and 8″ all contain 3 major elements, an elastic element, an axially movable conical hub, and a pulley or hub having an Archimedean spiral to convert the increasing force of the elastic element into a constant force. It can also be readily appreciated by a person of ordinary skill in the art that the present invention provides a number of qualities superior to known mechanisms. For example, the relatively simple construction of the present invention provides for manufacturing producibility. The present invention requires a generally small volume of space and is of relatively light weight. The working characteristics of the invention are generally similar to those dealing with weights (e.g., hubs, pulleys, ropes/cords). The choice of the force F is done without ratio. The present invention is readily adaptable to manual or electromechanical selection of the desired required force F and thus may be readily employed with a programmable system that controls exercises. With insignificant alternation of the construction, the device can be made generally “fool-proof” when a brake is installed which will be automatically put in motion in case of accidental or forced releasing of the user interface.

While a specific embodiment of the invention has been described in detail, it will be appreciated by those skilled in the art that various modifications and alternatives to those details could be developed in light of the overall teachings of the disclosure. Accordingly, the particular arrangements disclosed herein are meant to be illustrative only and not limiting as to the scope of the invention which is to be given the full breadth of the claims appended and any and all equivalents thereof. 

1. A resistance device for use with an exercise machine, the resistance device comprising: an arbor member structured to be rotatably coupled with respect to the exercise machine, the arbor member having a first end and an opposite second end; a first hub coupled to the arbor member, the first hub having a contact portion of variable radius; a cord member having a first end and an opposite second end, the first end being coupled to the arbor member at or about the first hub, the cord member wound about the first hub at the contact portion; an elastic element having a first end and an opposite second end, the first end being coupled to the second end of the cord member and the second end being structured to be coupled to a point fixed relative to the exercise machine; a second hub coupled to the arbor member, the second hub being structured to be coupled to a user actuatable member; and an adjustment mechanism coupled to the first hub, the adjustment mechanism being adapted selectively to vary the radius of the contact portion of the first hub.
 2. The resistance device of claim 1 wherein: the arbor member comprises a number of guide members coupled thereto; and the first hub comprises a conical shaped member of varying radius moveable with respect to the number of guide members by the adjustment mechanism.
 3. The resistance device of claim 1 wherein the adjustment mechanism comprises a crank member threadedly coupled to the first hub.
 4. The resistance device of claim 1 wherein the elastic element comprises a spring member.
 5. The resistance device of claim 1 wherein the elastic element comprises a beam member.
 6. The resistance device of claim 1 wherein the elastic element comprises a torsionally deflected member.
 7. An exercise machine comprising: a frame; a user actuatable member moveable relative to the frame; and a resistance device comprising: an arbor member structured to be rotatably coupled to the exercise machine, the arbor member having a first end and an opposite second end; a first hub coupled to the arbor member, the first hub having a contact portion of variable radius; a cord member having a first end and an opposite second end, the first end being coupled to the arbor member at or about the first hub, the cord member wound about the first hub at the contact portion; an elastic element having a first end and an opposite second end, the first end being coupled to the second end of the cord member and the second end being be coupled to a point fixed relative to the frame; a second hub coupled to the arbor member, the second hub being coupled to a user actuatable member via a flexible member; and an adjustment mechanism coupled to the first hub, the adjustment mechanism being adapted to selectively vary the radius of the contact portion of the first hub.
 8. The exercise machine of claim 7 wherein: the arbor member comprises a number of guide members coupled thereto; and the first hub comprises a conical shaped member of varying radius moveable with respect to the number of guide members by the adjustment mechanism.
 9. The exercise machine of claim 7 wherein the adjustment mechanism comprises a crank member threadedly coupled to the first hub.
 10. The exercise machine of claim 7 wherein the elastic element comprises one of a spring member, beam member, or torsionally loaded member. 